Project description:Transcriptome changes during leaf growth and development were profiled. We extracted RNA from Arabidopsis leaf number six from plants growing in stable and controlled experimental conditions at four different growth stages both at the end-of-day (EOD) and end-of-night (EON). The experiment was performed in short-day conditions with optimal soil water content, and for comparison also in conditions with reduced and stable soil water content. Four growth stages were selected for analysis: stage 1, with maximum relative area and thickness expansion rates coinciding with leaf emergence; stage 2, maximum area and thickness absolute expansion rates; stage 3, decreasing leaf area and thickness expansion rates, and stage 4, end of leaf area and thickness expansions.
Project description:The final size of plant organs such as leaves is tightly controlled by environmental and genetic factors that must spatially and temporally coordinate cell expansion and cell cycle activity. However this regulation of organ growth is still poorly understood. The aim of this study is to gain more insight in the genetic control of leaf size in Arabidopsis by performing a comparative analysis of transgenic lines that produce larger leaves under standardized environmental conditions. To this end, we selected five genes, belonging to different functional classes, that all positively affect leaf size when over-expressed: AVP1, GRF5, JAW, BRI1 and GA20OX1. We show that the increase in leaf area in these lines depends on leaf position and growth conditions and that all five lines affect leaf size differently. However, in all cases an increase in cell number is, entirely or predominantly, responsible for the leaf size enlargement. By means of analyses of hormone levels, transcriptome and metabolome we provide deeper insight in the molecular basis of the growth phenotype for the individual lines. A comparative analysis between them indicates that enhanced organ growth is governed by different, seemingly independent pathways. The analysis of transgenic lines simultaneously over-expressing two growth-enhancing genes further supports the concept that multiple pathways independently converge on organ size control in Arabidopsis.
Project description:The final size of plant organs such as leaves is tightly controlled by environmental and genetic factors that must spatially and temporally coordinate cell expansion and cell cycle activity. However this regulation of organ growth is still poorly understood. The aim of this study is to gain more insight in the genetic control of leaf size in Arabidopsis by performing a comparative analysis of transgenic lines that produce larger leaves under standardized environmental conditions. To this end, we selected five genes, belonging to different functional classes, that all positively affect leaf size when over-expressed: AVP1, GRF5, JAW, BRI1 and GA20OX1. We show that the increase in leaf area in these lines depends on leaf position and growth conditions and that all five lines affect leaf size differently. However, in all cases an increase in cell number is, entirely or predominantly, responsible for the leaf size enlargement. By means of analyses of hormone levels, transcriptome and metabolome we provide deeper insight in the molecular basis of the growth phenotype for the individual lines. A comparative analysis between them indicates that enhanced organ growth is governed by different, seemingly independent pathways. The analysis of transgenic lines simultaneously over-expressing two growth-enhancing genes further supports the concept that multiple pathways independently converge on organ size control in Arabidopsis. This SuperSeries is composed of the SubSeries listed below.
Project description:The final size of plant organs such as leaves is tightly controlled by environmental and genetic factors that must spatially and temporally coordinate cell expansion and cell cycle activity. However this regulation of organ growth is still poorly understood. The aim of this study is to gain more insight in the genetic control of leaf size in Arabidopsis by performing a comparative analysis of transgenic lines that produce larger leaves under standardized environmental conditions. To this end, we selected five genes, belonging to different functional classes, that all positively affect leaf size when over-expressed: AVP1, GRF5, JAW, BRI1 and GA20OX1. We show that the increase in leaf area in these lines depends on leaf position and growth conditions and that all five lines affect leaf size differently. However, in all cases an increase in cell number is, entirely or predominantly, responsible for the leaf size enlargement. By means of analyses of hormone levels, transcriptome and metabolome we provide deeper insight in the molecular basis of the growth phenotype for the individual lines. A comparative analysis between them indicates that enhanced organ growth is governed by different, seemingly independent pathways. The analysis of transgenic lines simultaneously over-expressing two growth-enhancing genes further supports the concept that multiple pathways independently converge on organ size control in Arabidopsis.
Project description:The final size of plant organs such as leaves is tightly controlled by environmental and genetic factors that must spatially and temporally coordinate cell expansion and cell cycle activity. However this regulation of organ growth is still poorly understood. The aim of this study is to gain more insight in the genetic control of leaf size in Arabidopsis by performing a comparative analysis of transgenic lines that produce larger leaves under standardized environmental conditions. To this end, we selected five genes, belonging to different functional classes, that all positively affect leaf size when over-expressed: AVP1, GRF5, JAW, BRI1 and GA20OX1. We show that the increase in leaf area in these lines depends on leaf position and growth conditions and that all five lines affect leaf size differently. However, in all cases an increase in cell number is, entirely or predominantly, responsible for the leaf size enlargement. By means of analyses of hormone levels, transcriptome and metabolome we provide deeper insight in the molecular basis of the growth phenotype for the individual lines. A comparative analysis between them indicates that enhanced organ growth is governed by different, seemingly independent pathways. The analysis of transgenic lines simultaneously over-expressing two growth-enhancing genes further supports the concept that multiple pathways independently converge on organ size control in Arabidopsis.
Project description:Plants grow continuously and undergo numerous changes in their vegetative morphology and physiology during their life span. The molecular basis of these changes is largely unknown. To provide a more comprehensive picture of shoot development in Arabidopsis, microarray analysis was used to profile the mRNA content of shoot apices of different ages, as well as leaf primordia and fully-expanded leaves from 6 different positions on the shoot, in early-flowering and late-flowering genotypes. This extensive dataset provides a new and unexpectedly complex picture of shoot development in Arabidopsis. At any given time, the pattern of gene expression is different in every leaf on the shoot, and reflects the activity at least 6 developmental programs. Three of these are specific to individual leaves (leaf maturation, leaf aging, leaf senescence), two occur at the level of the shoot apex (vegetative phase change, floral induction), and one involves the entire shoot (shoot aging). Our results demonstrate that vegetative development is a much more dynamic process that previously imagined, and provide new insights into the underlying mechanism of this process.